A vehicle with a fuel tank is equipped with an evaporative fuel processing device which is configured to process evaporative fuel generated in this fuel tank. An existing evaporative fuel processing device makes evaporative fuel, generated in the fuel tank, absorbed by an activated carbon in a canister, purges the evaporative fuel, absorbed by the activated carbon, with the fresh air by use of negative pressure generated in an intake pipe, and introduce it into the intake pipe to combust it in an engine. However, in the case where the intake pipe is provided with a compressor of a supercharger, a part downstream of this compressor becomes positive pressure during supercharging, and therefore it is not possible to purge evaporative fuel, absorbed by the activated carbon, by use of negative pressure.
To cope with this, an evaporative fuel processing device described in Japanese Utility Model Registration Application Publication No. Sho 63-152965 is provided with a purge pump (more specifically a venturi) in a passage through which the downstream side and the upstream side of a compressor communicate with each other, and connects the purge pump and a canister to each other with a purge passage. During supercharging, a part downstream of the compressor becomes a higher pressure than apart upstream of the compressor, and thus the air flows from the downstream side to the upstream side of the compressor in the passage through which these parts communicate with each other. This flow of the air generates negative pressure in the purge pump, which makes it possible to purge evaporative fuel, absorbed by an activated carbon in the canister, even during supercharging.
Meanwhile, in the evaporative fuel processing device described above, the purge pump is secured on an intake pipe with screws and bolts etc., but they are sometimes detached or broken unintentionally due to various reasons such as vibration of the vehicle and failing to fasten them during maintenance. However, in the existing evaporative fuel processing device, the air flows in the purge pump from the downstream side of the compressor toward the atmosphere even when the purge pump is detached from the intake pipe, and therefore negative pressure is generated and the evaporative fuel absorbed by the activated carbon might flow out to the atmosphere.
There is a need to provide an evaporative fuel processing device and a fluid processing device capable of inhibiting evaporative fuel from flowing out even when an anomaly occurs in a purge pump.